Heat exchange construction



July 28, 1959 R. W. AYLING HEAT EXCHANGE CONSTRUCTION Filed March 1, 1957 air flow FIG. 4

INVENTOR.

ROBERT W. AY LING.

ATTORNEY.

United States Patent 9 HEAT EXCHANGE CONSTRUCTION Robert W. Ayliug, Syracuse, N.Y., assignor to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Application March 1, 11957, Serial No. 643,426

Claims. (Cl. 62-285) This invention relates to an improved finned tube heat exchanger construction which will facilitate the drainage of condensate which forms on the exchanger. This invention also relates to a method of making the improved heat exchanger.

In many applications where a cooling medium is passed through a heat exchanger and where air or another gas comes into contact with the outside of the heat exchanger, the formation of condensate on the external surfaces of a heat exchanger often reduces the efliciency thereof because this condensate acts as an insulating layer which lessens the heat transfer characteristics. Furthermore, when heat exchange members are used in a refrigeration circuit, liquid which forms on the coil being defrosted tends to adhere to its surfaces. The stagnation of this moisture is objectionable because it not only increases the relative humidity of the enclosure being cooled when the refrigeration circuit is placed on the cooling cycle, but also tends to freeze into a solid sheet of ice which acts as an insulating layer to decrease the efiiciency of the heat transfer operation. It is therefore desirable to dispose of this condensate in a simple and efficient manner. It is for this purpose that the present invention is contemplated.

It is the chief object of this invention to provide an improved heat exchanger construction which will readily facilitate the disposal of condensate which forms there- It is another object of this invention to provide an improved heat exchanger construction which facilitates the removal of condensate from its surface in a simple and eflicient manner and which can be constructed at a low cost.

It is still. a further object of this invention to provide a condensate disposal means for a heat exchanger which will not interfere with proper operation of the heat exchanger. Other objects and attendant advantages of the present invention will readily be perceived hereafter.

The present invention relates to an improved heat exchanger containing condensate disposal means and comprises a conduit for the passage of a heat exchange medium. Fin elements are affixed to the outside of the conduit and are adapted to be contacted by a gas containing moisture. Certain portions of the fin elements are at a higher level than other portions. Lips are formed on the lower portions of adjacent fin elements, and these lips are bent downwardly so that each lip extends toward the lip of an adjacent fin element. Thus condensate which forms on the fins will flow from the higher portion thereof to the lower portion wherein the lips are located. Because each lip extends toward an adjacent lip, a path is provided for the condensate to flow down these lips. In this. manner the hanging up of condensate on the heat exchanger surfaces is avoided to a great degree. This invention will be more readily understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein:

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Figure l is a fragmentary view of a heat exchanger tube having the condensate disposal construction of the present invention;

Figure 2 is a view taken along line IIII of Figure 1;

Figure 3 is a modification of the structure shown in Figure 1;

Figure 4 is a further modification of the present invention; and

Figure 5 illustrates the finned heat exchange tubes inserted into a heat exchanger construction.

Reference is now made to Figure 1, wherein numeral .10 depicts a tube for the passage of a cooling medium. Afiixed to outside of. tube 10 is a helical fin 11. At every convolution fin 11 is slitted as at 12 and a portion of fin 11 immediately adjacent each slit,is formed into a downwardly extending lip 13. As shown in Figure 1, the lower portion 14 of each lip 13 may be in contact, with the upper portion of the lip which is immediately below it.

The finned heat exchange tube 10 of the above described construction is adapted to be utilized with the axis thereof extending in a substantially vertical direction. It can readily be seen that as condensate forms on each convolution of the fin between the adjacent lips, this moisture will fiow downwardly along said fin 11 until lip 13 is reached. The condensate will then flow from each lip directly to the lip below it. Thus prolonged contact of the condensate with the fin 11 is avoided.

In Figure 3, a modified construction of the structure of Figure 1 is shown. The structure of this modification is similar to that shown in Figure l in all respects except in the shape of the lips. Lips 15 are formed by a suitable deforming operation into the shape of a spout. The superposed spouts 15 are in contact with each other at points 16. This construction functions generally in the same manner as that of the Figure 1.

In Figure 4, a still further modification is shown wherein fluid conducting tube 17 has a plurality of annular discs 18 placed on the outside thereof to facilitate the heat exchange function. Spouts 19 are formed by any suitable metal deforming operation, such as drawing, so that a portion of the lower edge 20 of each spout is in contact with the upper edge of the spout directly below it. This construction operates most satisfactorily in applications where tube 17 or the discs 18 are tilted at an angle to the vertical so that the upper borders of spouts 19 are at the lowermost portions of the discs 18 on which they are formed. Thus any condensate forming on the discs 18 will run down toward the spouts 19 and then from one spout to another till the bottom of the heat exchanger is reached.

In Figure 5, heat exchanger tubing made in accordance with any of the foregoing described ways is shown inserted into a heat exchange unit 21 in the form of a serpentine coil. It can readily be seen from Figures 2 and v5 that the air flow is from the direction remote from where the lips are formed. In other words, the fluid conducting tube 10 is directly between the point from which the air is coming and the lips. Thus the lips do not form a barrier for the air flow so as to create unnecessary turbulence. However, if a certain amount of turbulence is desired, the lip portions of the heat exchanger can be placed in any suitable position to obtain the desired results. It is to be also noted that the modification of Figure 1 can be made so that both portions of the fin adjacent to slit 12 may be formed downwardly into lips rather than just one portion -14 as shown.

It can thus be seen that I have described a simple and eflicient condensate disposal arrangement for a finned heat exchange tube which can be fabricated at extremely low cost and with a small amount of labor.

While I have described preferred embodiments of the invention it will be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

I claim: a v

1. A heat exchange member comprising a substantially vertically extending tube, a helical fin on the outside of said tube, and lips on'said helical fin for conducting condensate therefrom.

2. A heat exchange member as set forth in claim 1 wherein said lips are in the form of spouts.

3. A heat exchange member comprising a substantially vertically extending tube, a helical fin on the outside of said tube, lips on said helical fin at each convolution thereof, each lip being in contact with an adjacent lip.

4. A heat exchange member, according to claim 1, in which lips are provided on adjacent convolutions of the helical fin in superposed stacked relationship.

5. A heat exchange-member comprising a conduit for the passage of a heat exchange medium, fin elements on said conduit with portions thereof at a higher level than other portions and lips on said fin elements for conducting condensate away from said fin elements, said lips being formed on adjacent fin elements in superposed stacked relationship, each lip being in contact with an adjacent lip.

References Cited in the file of this patent UNITED STATES PATENTS 1,250,884 Hubbert Dec. 18, 1917 2,286,271 Higham June 16, 1942 15 2,427,200 Dreier Sept. 9, 1947 FOREIGN PATENTS 149,251 Austria Apr. 10, 1937 

